The present invention is generally directed to testing capacitance of a circuit. In particular, the present invention is directed to a device and method for detecting the capacitance of a circuit coupled to an output of a driving circuit.
Testing capacitance of a circuit has long been performed. Testing capacitance of a circuit coupled to an output of a driving circuit (e.g., an IC chip) has posted a new challenge. Nowadays, integrated circuits chips are widely used to control or drive a variety of actuators (e.g., micro actuator, MicroElectroMechanical Systems (MEMS) actuator). For example, ICs are used in electronic appliances such as cameras to control or drive a motor that drives an adjustable mechanical component (e.g., a lens). An actuator coupled to an IC chip may appear as a capacitor coupled to an output pin of the IC chip.
It would be desirable for an IC chip to test capacitance of a circuit coupled to an output of the IC chip (e.g., to determine on its own whether a load device is connected to chip pin before driving the pin with an activating current.) No known tests are available that provide a simple, inexpensive circuit for this purpose. Accordingly, there is a need in the art for a circuit that efficiently tests for capacitance of a circuit coupled to an IC pin with minimal complexity.